The invention relates to a strapping apparatus for strapping articles with a strapping band, having a base plate which is provided with a base surface for arranging on an article, having a tensioning device with which a band tension can be applied to the strapping band, the tensioning device being provided for this purpose with an actuable tensioning tool which can be brought into and out of contact with the band, having a sealing device with which, by contact with the band, two band layers can be permanently connected to each other by forming a seal between the two band layers, the sealing device being provided in this case with a counter-holder surface for bearing against one side of the band and a sealing head for bearing against another side of the band while a seal is produced, and being provided with a clamping device with which the band can be clamped in the strapping apparatus.
Mobile strapping apparatuses of this type, like the strapping apparatus according to the invention, are used for strapping articles with a plastics strap. For this purpose, a loop of the particular plastics strap is placed around the article. The plastics strap is generally pulled off here from a supply reel. After the loop is completely placed around the article, the end region of the band overlaps with a section of the band loop. The strapping apparatus is then applied to said two-layered region of the band, the band is clamped in the process in the strapping apparatus, a band tension is applied to the band loop by means of the tensioning device, and a seal is produced between the two band layers by friction welding at the loop. In this connection, pressure is applied to the band in the region of two ends of the band loop by a friction shoe moving in an oscillating manner. The pressure and the heat arising because of the movement melt the band, which generally contains plastic, locally for a short time. This results in a permanent connection, which at the most can be released again with a great force, between the two band layers between the two band layers. At the same time, the loop is severed from the supply reel. The respective article is thereby strapped.
Strapping apparatuses of the type in question are provided in particular for mobile use, in which the units are intended to be carried along by a user to the particular use location and are not intended to be dependent there on the use of externally supplied mains power. In the case of previously known strapping units, the power required for the designated use of such strapping units for tensioning a strapping band around any article and for producing a seal is generally provided by an electric battery or by compressed air. Mobile strapping apparatuses of the type in question are frequently in permanent use in the goods packaging industry. Therefore, as simple an operation of the strapping apparatuses as possible is sought. This is intended, firstly, to ensure high functional reliability of the strapping apparatus and, secondly, the smallest possible loads for the operators.
The operation of the strapping apparatus also includes the fact that, after production of the seal between the two band layers, the band has to be removed again from the strapping apparatus. In this connection, it is frequently apparent that the band can be removed from the strapping apparatus only with energy and effort rather than easily, although the tensioning device, the clamping device and the sealing device release the band.